Lion

Your enemy the devil prowls around like a roaring lion looking for someone to devour.

1 Peter 5.8

E.Clowney (BST):

The fact that Satan has been cast down from heaven and knows that his time is short makes him, in a sense, a more formidable adversary.

He [Satan] is filled with fury, because he knows that his time is short.

Rev 12.12

His fury against the Lord and his kingdom is the more intense. He may threaten the church from within, masquerading as an angel of light (2Cor 11.14; Acts 20.29). He may rage from without, using the fire and sword of persecuting tyrants. But the Christian knows that "the God of peace will soon crush Satan under your feet" (Romans 16.10). James, in his parallel passage, says, "Resist the devil, and he will flee from you." (James 4.7). The danger to the Christian is not that he is helpless before the devil. He is equipped with the whole armour of God: the shield of faith will extinguish the flaming darts of the evil one (Eph 6.10-18). The danger to the Christian is that he will fail to resist, that he will not watch and pray, that he will not put on the whole armour of God and take the sword of the Spirit...

Peter calls on us to do what he had failed to do in the garden of Gethsemane: to watch and pray. [Then he fell to the temptation to deny Jesus.]

Roaring Satan is a tethered lion. He cannot tempt us beyond what we can endure, for God will not permit it (1 Cor 10.12-13)..... If Satan is to be resisted, sober watchfulness is called for. Sobriety includes both alertness and realism (1.13; 4.7). Satan can be resisted only in a firm and settled faith.